This invention relates generally to reinforced, plastic composites and, more particularly, to the preparation of preforms which are useful in the fabrication of such composites.
Plastic composites having contoured shapes and surfaces are known in the art. For example, since the advent of ultra-high strength aramid fibers, protective helmets have been made by laminating woven fabrics impregnated with a resin as a binder and heat curing the laminate in a mold of the desired shape. In U.S. Pat. No. 4,199,388, Tracy et al. recognized the expense of composites reinforced by fabrics and disclosed an alternate route involving the preparation of plural preforms The preforms can be nested and molded into the desired shape. Each preform includes a screen onto which a strand of fibers is deposited randomly from an air gun. The disadvantages of such a contoured composite are the lack of precision in the deposition of reinforcing fibers in each preform and the absence of uniformity between the preforms.
In German Pat. No. 3,003,666, the possibility of arranging the reinforcement for a composite structure on an arched table is disclosed. Such a table and an array of pins are shown in FIG. 9. According to the description, a reinforcing strand would be wound, in aligned rows, between opposed pins.